最病 A Different approaches n Naive, extreme approaches: 口F。 orsake previously stored object a Over a migration path from old format to new a one-time en masse conversion of old objects not applicable to a large persistent store or to one that must be available continuousl a Most general solution: On-the-fly conversion n Note: We cover only the retrieval part. Whether to write back the converted object is a separate issue Institute of Computer Software 2021/1/28 Nanjing UniversityDifferent approaches  Naive, extreme approaches:  Forsake previously stored objects  Over a migration path from old format to new ◼ a one-time, en masse conversion of old objects ◼ not applicable to a large persistent store or to one that must be available continuously  Most general solution: On-the-fly conversion  Note: We cover only the retrieval part. Whether to write back the converted object is a separate issue. 2021/1/28 Institute of Computer Software Nanjing University 48